You can make different profiles for each of the substrates on which you print—or if you’re printing on a wide variety of materials, you might group similar materials into one overall profile. Clearly, the more specific the profile you create, the more accurate and consistent your color will be.

Once you print the color grid on your device, use a spectrophotometer to read the printed color values. Profiling software compares the printed piece with the known color values. The profile is actually the software’s best attempt to match the output of the printing device to the known values. What it attempts to do is correct the output to match the original as closely as possible. In truth, it will never be an exact match. All print- ing devices are a little bit different (Figure 1), even those that are made in the same factory at the same time.

To create the profile, the operator reads the individual color squares on the printed target (Figure 2), and the software compares the values read with the known color values of the original image. There can be anywhere from a couple hundred to a few thousand squares to be read, and the more squares on the target, the better the profile will be. It is easy to see why it can pay to buy an auto- mated reader. Reading small, individual squares by hand is tedious and time consuming, not to mention error prone.

The quality of your calibration and profile depends a lot on the software, targets, and spectrophotometer used, as well as the color algorithms plugged into the software. In general, the more you pay for software and hardware, the better the profile. But it’s also true that even the most basic machines offer pretty good results.

What is color gamut?

Another way to describe color gamut is the color space in which every color-sensing device operates. The device could be a human eye, a computer monitor, or a printing press. You might be surprised to learn that no two people see color exactly alike. And even though a spectrophotometer is better at seeing color than the human eye is, it’s even true that two different machines will read the exact same color grid slightly differently.